Both Vonn and Woods, who is a 14-time major golf champion, also posted photographs of themselves on their Facebook pages.

"Our relationship evolved from a friendship into something more over these past few months and it has made me very happy," Vonn said on her Facebook page. "I don't plan on addressing this further as I would like to keep that part of my life between us, my family and close friends."

As ESPN explains, Woods has two children with his ex-wife Elin Nordegren, a former Swedish model.

"The marriage dissolved after Woods' infidelities very publicly came to light in 2009," ESPN adds. "His career then suffered for a time, but he has shown signs of again becoming the top threat on the tour and won the WGC-Cadillac Championship this month. Woods is in the field for this week's Arnold Palmer Invitational."

Vonn, whose divorce from fellow Olympic ski racer Thomas Vonn became official in January, is recovering from a knee injury she suffered during the World Championships in Austria.